A FAU-based zeolitic imidazolate framework composites for efficient separation of C2H2/C2H4

Abstract

Adsorptive separation of C₂H₂ from C₂H₄, which could deal with multi-steps for their similar kinetic diameter and physical properties, still poses a significant challenge. In this work, we prepared two metal cations (Co²⁺, Zn²⁺)-exchanged aluminosilicate FAU zeolites as an inorganic porous matrix, and grafted an organic zeolitic imidazole framework crystal layer to construct the inorganic–organic composites for gas separation process of C₂H₄ among the mixed gas components. Such inorganic–organic porous composites can adsorb C₂H₂ and hinder the large-sized C₂H₄. The Co-FAU@ZIF-8 composite was verified through breakthrough experiments and demonstrated a promising adsorptive volume of 1.46 mmol g⁻¹ with an IAST selectivity of C₂H₂/C₂H₄ of 5.6 at 298 K, respectively. Via powder X-ray diffraction crystallography and combined spectroscopy, we found that the exchanged metallic cation located at the accessible s6r, and served as the anchor point for the epitaxy of different crystals. Such tunable features (i.e., metallic centers and pore diameter) provide a potential pathway for the sub-sequential development of highly efficient adsorptive materials.